Water vapor and the climate, why carbon dioxide is a very minor player

Water vapor is a powerful greenhouse gas, but its net effect in the atmosphere is to lower temperatures.  Proponents of anthropogenic global warming (AGW) and most IPCC climate models assume the opposite:

AGW hypothesis: Carbon dioxide, a weak greenhouse gas, begins warming the planet.  This warming evaporates water and so puts water vapor into the atmosphere which amplifies the warming effect.  This is called a positive feedback.

At first look, this proposition seems logical and reasonable.  But other properties of water vapor reduce temperatures and the net effect is a strong negative feedback.  A positive feedback tends to destabilize a system, whereas, a negative feedback tends to keep a system in check.  Just think for a minute, if water vapor had a net positive feedback effect, this planet would have had run-away global warming long ago.  That alone should falsify the positive feedback hypothesis.  But let’s look at some observational evidence for a negative feedback.

The graphic below  (from Brehmer) compares four pairs of cities, each at about the same latitude so that each pair receives about the same amount of sunlight, and the cities are inland, away from possible tempering by sea breezes. The data is from the National Weather Service  (the temperatures have been corrected for elevation differences). The difference between the pairs is that one city is in an arid climate, the other is in a humid climate.  We see that the more humid city in each pair has a lower average annual temperature.  The addition of water vapor to the atmosphere has a cooling effect in spite of water vapor being a greenhouse gas much more powerful than carbon dioxide.


I’ll show another piece of observational evidence (from Sweger).  This shows humidity versus temperature measured daily at 3p.m., the hottest part of the day.  Again we see a negative correlation of temperature with humidity, i.e., higher temperatures occur when humidity is lowest.


I will mention one more example, Al Gore’s favorite graph.  This is the sawtooth graph showing the rise and fall of temperatures and carbon dioxide during the last few glacial-interglacial periods.  I ask, if rising carbon dioxide is further amplified by water vapor, why would the carbon dioxide and temperature rise terminate?  Could it be that other natural forces are much stronger than the effect of carbon dioxide?

Conventional greenhouse theory holds that the sun’s energy passes through a relatively transparent atmosphere (in absence of clouds and aerosols) and heats the surface of the earth.  The surface radiates energy in infrared wave lengths back into the atmosphere.  Some of that energy is absorbed by greenhouse gases, including carbon dioxide and water vapor, and some is re-radiated back toward the surface, thereby raising temperatures.  Why then, does the presence of water vapor, a strong greenhouse gas, cause cooling?  The answer lies in the properties of water.

First, it takes heat energy to turn liquid water into water vapor.  This is the latent heat of vaporization which absorbs heat energy without changing temperature. Likewise is the latent heat of fusion.  It takes heat energy to change ice to liquid water, again without changing temperature.

Second, is the great heat capacity of water and water vapor, i.e., the ability to store heat energy. Since hot air rises, the contained water vapor transports heat away from the surface by convection.

The third property is related to the second.  Water vapor is relatively transparent to incoming solar radiation in the visible part of the spectrum, but is an excellent absorber of infrared radiation.  This capacity warms the water vapor and heat is transported away by convection.  Sweger notes, “that the IR absorption of carbon dioxide  on solar irradiance  is of marginal effect since the absorption by water vapor is virtually 100% without any contribution from carbon dioxide.”  That may be overstating it a bit, but not by much since there is usually at least 60 times more water vapor in the atmosphere compared to carbon dioxide.

And, of course, more water vapor in the atmosphere produces clouds which reflect incoming sunlight back into space, so it never reaches the surface to contribute to the greenhouse effect.

We see from direct observation that water vapor tends to moderate global temperatures.  As Dr. Roy Spencer notes, “The question of how much warming will result from adding carbon dioxide to the atmosphere is what we skeptics are skeptical of. The climate system is amazingly complex, and the IPCC position that elements within the climate system (especially clouds) will change in ways which amplify the resulting small warming tendency is highly questionable, to say the least. If the climate system instead acts to reduce the warming, then anthropogenic global warming (AGW) becomes for all practical purposes a non-issue.”


Earth’s climate engine by Dr. Daniel M. Sweger [link]

The greenhouse effect…explored, by Carl Brehmer [link][Link2]

The Alabama two step by Dr. Roy Spencer [link]



  1. Jon, I hope you noticed what Dr. Spencer had to say about your “saturation” argument. It was in the same post you quote from. Would you like to set the record straight right now about “CO2 Saturation”.

    You are correct that heat from the surface is absorbed by water vapor. You are also correct that some of that latent heat of evaporation is moved upwards by convection. But you’re neglecting a key step. Latent heat is a two way street. You mention “the latent heat of vaporization”, but leave out the “latent heat of condensation.” As one moves higher in the atmosphere, we encounter rapidly cooling temperatures. And what happens when water vapor cools? It condenses and RELEASES that latent heat in the form of clouds, rain and other precipitation. And it does so almost entirely in the lowest layer of the atmosphere. The area of the atmosphere were we experience weather. And over the long term, Climate. It does NOT release this heat by “dumping it into space”, as you have said. It would be more accurate to say it dumps it in our backyard.

    CO2 has much different properties. It is a NON-condensing gas. It does not precipitate out of the low layers of the atmosphere. It keeps absorbing heat and reradiating it right on up to the top of the atmosphere, TOA. That’s one reason why such a small quantity can have such a large effect. 

    One glaring problem with your study of the four pairs of cities is their latitudes. None are in equatorial or polar regions. Just imagine cities in the tropics. Extremely high humidity and extremely high temperatures. And what about areas near the Polar regions? Extremely low humidity and extremely low temperatures. AGW is global. The data input used to assess it must be global. Why did Brehmer pick these cities? Why not compare the easily available Global datasets? (That’s a rhetorical question.) Just to show how strained this logic is: Checkout the locations of the only two cities even marginally outside the midlatitudes. Riyadh, in the middle of the Saudia Arabian desert; and, Bogra, right at the base of the tallest mountain range in the world. Think that might effect the local climate a little? 

    Jon:  “I ask, if rising carbon dioxide is further amplified by water vapor, why would the carbon dioxide and temperature rise terminate?” A physicist would answer: “Because the ‘Stefan-Boltzmann Law demands it”. Radiation from a planet increasing in proportion to the fourth power of temperature, in accordance with the Stefan-Boltzmann law, provides a negative feedback; so the positive feedback effect has to be very strong to cause a runaway effect. A simpler answer: CO2, temperature and water vapor are not the only factors that regulate climate. Just because you turn your thermostat all the way up, doesn’t mean the temperature in your living room will eventually melt your TV.

    Jon likes to throw this out there periodically, to see if your paying attention: “And, of course, more water vapor in the atmosphere produces clouds which reflect incoming sunlight back into space, so it never reaches the surface to contribute to the greenhouse effect.” Low clouds reflect heat, but high clouds TRAP heat. It’s the change in the proportion of each that determines the NET heating or cooling (As well as the relationship of water vapor volume to cloud albedo). Dr. Spencer has been trying for years to find a mechanism that could tip the balance in a negative direction. He’s a brilliant man, but he has so far failed to find that mechanism.   JP

    1. Wow John, I think your second to last paragraph just destroyed the AGW argument.

      BTW the Sweger reference discusses Stefan-Boltzmann in detail.

      1. Jon, It nearly destroys the “runaway” greenhouse effect. And it’s why the IPCC says: “a “runaway greenhouse effect” — analogous to Venus – appears to have virtually no chance of being induced by anthropogenic [human] activities.” It does not destroy AGW. Leave your thermostat on ‘high’, and it’ll still get way too hot. It just won’t melt your TV.

        Are you going to set the record straight about the “CO2 saturation” argument? JP

  2. John, 

    In the Spencer reference, he says, “the CO2 absorption bands are already mostly saturated…but the wings of those bands are not,…”  The “mostly saturated” reflects that the theoretical warming effect of CO2 is logarithmic meaning that it takes more and more to have the same effect.  Of course they can never become completely saturated but for all practical purposes the bands are almost saturated so addition CO2 has very little effect.

    The AGW contention is that CO2 is the major cause of warming and that if we don’t do something about it we will suffer all kinds of “tipping points” and disasters.  You essentially admitted in the second to last paragraph you wrote: “CO2, temperature and water vapor are not the only factors that regulate climate.”  I agree with that statement and further maintain that the “other factors” are what truly control the climate.  The positive forcing of CO2 is insufficient to overcome the negative feedbacks.

    Latent heat of vaporization/condensation are just different directions of the same phenomenon.

    Finally, your problem with the cities presumes that if different cities were picked, we would have different results. Prove it.  If you had read the Sweger reference you would see that one of his example cities was Nairobi, Kenya, which is almost on the equator.  

    You say “AGW is global” so then it must obey the same principles globally,  and the research I presented shows that at least on some parts of the globe, water vapor greatly diminishes the theoretical forcing effects of carbon dioxide.

    1. Jon, Yes, the rate of absorption by CO2 is logarithmic. And you 
      are correct that that means it “takes more and more to have the same effect”. But guess what else is logarithmic? Our emission levels of CO2. So the need to have “more and more” is being satisfied. That’s why the effect is still progressing. You leave out this quote from Dr. Spencer: “This is already accounted for in the climate models used by the IPCC.” Your assertion that 
      “addition [of] CO2 has very little effect” would be true, IF our emissions were not also increasing logarithmically. But they are, and it isn’t.

      I didn’t “essentially admit” that many different forces regulate climate. I unequivocally stated it. There is absolutely no question about it. What you seem to fail to recognize is that anthropogenic CO2 forcing and it’s feedbacks are ADDED to those cyclic historical forcings and feedbacks. When you assume that present warming is caused by one or more of  those cyclic mechanisms, you haven’t solved a mystery. You just created one. What mechanism inactivates the anthropogenic CO2 forcing?

      You say that “the positive forcing of CO2 is insufficient to overcome the negative feedbacks”.  I assume you mean anthropogenic forcing of CO2. That being the case, What “negative feedbacks” are you talking about? 

      “Latent heat of vaporization and latent heat of condensation are just two directions of the same phenomenon.” Yes, the enthalpy. And you left out the half that leaves the heat in our lower atmosphere, where it effects our climate. 

      If I choose “different cities”, I would be repeating the same error that you and Brehmer have made. No one get’s “to pick” the cities that support their contention and ignore those that don’t. The Global measurements are what’s necessary to give Global results. And that’s what the IPCC and Dr. Spencer have done with their modeling. They’ve properly used Global datasets. You and Brehmer have not. 

      I highly recommend that you and your readers visit Dr. Swegers website here:   http://gettingready.net/default.htm

      The “…research I  presented shows that at least on some parts of the globe water vapor greatly diminishes the theoretical forcing effects of carbon dioxide.” No you didn’t. You showed a correlation between temperature and humidity for eight handpicked cities, with no description whatsoever of a causal mechanism.   JP

      1.  But guess what else is logarithmic? Our emission levels of CO2.” Really? Where did you get that information? 

      2. Here is what a logarithmic function looks like when plotted with linear axes.  Your example is not logarithmic; it is linear.

      3. Jon, You are right and I was wrong. The effect of CO2 on temperature is logarithmic but the rate of emissions has been logarithmic only on short time scales. Thanks for the correction. JP

      4. Jon, My browser won’t link to the little graphs on disqus. Could you paste in the full URL for me?

        David Hoffman of the Earth Systems Research Lab at NOAA (the folks that monitor Mona Loa CO2) was the source for my statement on the rate of CO2 emissions. He and his team state that human CO2 emissions have been rising at an exponential rate for 50 years. Like you, I just don’t understand that claim. I’ve got a call into him and I’ll let you know how he comes to that conclusion. JP

      5. Jon, If you could include the URL in future graphs, it would help. I get the concept of the logarithmic function being the inverse of the exponential function, which is why the graph from NOAA made sense when accompanied by Hoffman’s statement. I think you’re correct, but I’ll see what he has to say for himself and let you know. JP

  3. This article from skeptical science does a very good job of illustrating what the relationship of the earth’s energy balance is.
    quote:Just think for a minute, if water vapor had a net positive feedback effect, this planet would have had run-away global warming long ago.  That alone should falsify the positive feedback hypothesis. :unquote
    Radiative Balance, Feedback, and Runaway Warming
    First, we begin with the simplest case in which the Earth has no atmosphere and essentially acts as a perfect radiator. In this case, the outgoing radiation is given by the Stefan-Boltzmann equation OLR=σT4.
    Source: Skeptical Science (http://s.tt/17JlO)
    Figure 1: Plot of OLR vs. Surface temperature for a perfect blackbody
    Earth with no atmosphere and the relationship is very simple and clear. The
    stephen boltzman equation applies clearly.
    Going to figure 2 its easy to see that co2 increases the resistance to OLR (outgoing longwave radiation) and the heat begins to  build up in the atmosphere.
    Going to figure three and the writer adds in water vapor feedback. The same amount of energy coming in from the sun increases the temperature at the surface of the earth a great deal more than just co2 by itself. This is the argument that the IPCC is making along with the 97% peer reviewed scientists in climatology. This figure ties in with  climate sensitivity. This helps to illustrate the 3*C sensitivity for a doubling of co2.
    Skipping to figure 5 helps to illustrate runaway global warming. By this example the author increased the input of the sun to show what the response of the atmospheric temperature would be. Here it shows the water vapor curve flattening out before it reaches the upper green line where the earth’s energy balance takes place.
    We don’t have a Venus situation. Although Venus is a very good example of co2 run amok. 

    1. It is a common misconception that Venus is an example of CO2 run amok.   There is little or no greenhouse effect on Venus:

      Venus has a surface temperature of about 900̊F and an atmosphere composed of 96% carbon dioxide. The temperature is the same from equator to poles, from day to night (Venus rotates on its axis in 2,802 hours rather than 24 hours). Venus is often touted as the extreme example of run-away greenhouse warming.  But, there is almost no greenhouse warming on Venus because little, if any, direct sunlight gets to the surface. The atmosphere is too thick.  In 1975, the Russian Venus lander Venera 9 measured clouds that were 30–40 km thick with bases at 30–35 km altitude.  The surface air pressure on Venus is about 92 times greater than that on Earth.  The high pressure alone can explain most of the high surface temperature.  Although Venus gets almost twice the solar irradiation of Earth, Venus’ high albedo reflects back 65% of the sunlight. Venus has almost no water vapor in the atmosphere (about 0.002%), and therefore lacks the major greenhouse gas that Earth has.  

      Mars has an atmosphere composed of 95% carbon dioxide and only a trace of water. Its atmosphere is very thin. Its surface pressure is about 2% that of Earth. The temperatures on the two Viking landers, measured at 1.5 meters above the surface, range from + 1° F, ( -17.2° C) to -178° F (-107° C). However, the temperature of the surface at the winter polar caps drop to -225° F, (-143° C) while the warmest soil occasionally reaches +81° F (27° C) as estimated from Viking Orbiter Infrared Thermal Mapper (NASA data). Again, no water vapor, no greenhouse effect.

      1. BTW the skeptical science figure 5 postulates something that does not happen in nature on the earth.

      2. If you understand the graph correctly it would be earth responding to a brighter higher energy output of the sun. It could happen with very little possibility of it happening in our present circumstances. The point of the exercise that you haven’t acknowledged is that water vapor is clearly a pos feedback. As JP has pointed out, water vapor is a condensing ghg while co2 is a noncondensing ghg. co2 will be around for centuries and is the driver of water vapor in the atmosphere. The two are clearly in concert together for better or worse.

      3. Venus is the way it is entirely because of the green house effect.

        quote:Just think for a minute, if water vapor had a net positive feedback effect, this planet would have had run-away global warming long ago.  That alone should falsify the positive feedback hypothesis. :unquote

        You are a public speaker making mistakes in your understanding of science. The article from Skeptical science makes a very clear bright illustration of how water vapor is a positive feedback. You have a responsibility to get your science correct before you publish.

        quote: Again, no water vapor, no greenhouse effect.:unquote

        At one point you say water vapor did not have a pos feedback and here you say no water vapor, no greenhouse effect. You can’t have it both ways.

        You are entitled to your opinions, but that does not mean they are facts.

        quote: Although Venus gets almost twice the solar irradiation of Earth, Venus’ high albedo reflects back 65% of the sunlight. Venus has almost no water vapor in the atmosphere (about 0.002%), and therefore lacks the major greenhouse gas that Earth has.:unquote

        This actually sets up my point. Venus gets twice the radiation that earth does and yet reflects 65% of the sunlight hitting it. WHich would suggest to me based on your take on Venus, its actually getting similar radiation that earth does. And yet it maintains 900*C at its surface. It does that because the heat is kept in by the co2 doing an extremely effective job at reflecting heat back to the surface. By the way earth is now doing this more efficiently due to increased co2 and other ghg’s in the atmosphere.

      4. Go back a reread the post.  Water vapor has an initial positive feedback, but later turns negative because of convection.  The NET effect is negative feedback.
        On Venus, if sunlight can’t reach the surface to heat it and cause outgoing infrared radiation, there is no greenhouse effect by definition.

      5. Jon, You have shown no evidence that water vapor has a negative feedback on Earth’s energy budget. You present two unpublished (for very good reason) opinion pieces that purport to  show the localized effects of humidity. Sweger and Brehmer describe mechanisms that move heat around in the system, but no new mechanism for moving it out of the atmosphere. Neither have shown how any of the universally accepted radiative transfer equations are incorrect. If they had, Dr. Spencer or Dr. Lindzen would have jumped on it with both feet.   

        Additionally, Jon, I got in touch with NOAA/ESRL. Unfortunately David Hoffman passed away, but I’m communicating with them to better define the nature of the rate of CO2 emissions. I’ll let you know the results.

        I’ve looked more closely at the graph you showed on the logarithmic function of atmospheric CO2 absorption (I found the original source) and the nature of the confusion became apparent. That graph has the CO2 increasing on the ‘x’ axis.  Because the independent variable is normally on the ‘x’ axis and the dependent variable on the ‘y’ axis, graphs that show the rate of CO2 emissions over time normally have the CO2 function on the ‘y’ axis, as time is considered the independent variable. This led to my confusion about the rate chart being logarithmic. If the axes are ‘flipped’, it is logarithmic. This is of course dependent on the original function being exponential. This may turn out to be a case of us using the term exponential a little loosely. I believe (and will let you know when ESRL gets back to me) that Hoffman may be using that term because the rate can be described by an exponential equation having a polynomial exponent.   

        The nomenclature issue aside, the point I was making still stands. As you said, “it takes more and more [CO2] to have an effect”. And that’s just what we are getting, “more and more” CO2. And Dr. Spencer was correct when he said this about the “saturation” argument: “This is already accounted for in the climate models used by the IPCC”. If you look closely at your graph, you’ll notice  Charnock and Stine estimate the climate sensitivity at 2.92 degrees C. Right in the middle of IPCC projections.   JP

      6. Convection is not a feedback. Thank god there is convection or it would be hotter at the surfaace than it is. Water vapor is the higher form of energy of water and (latent heat) that is the negative feedback. Rain. The energy content of the atmosphere does not change because the air is moved around.

        quote:On Venus, if sunlight can’t reach the surface to heat it and cause outgoing infrared radiation, there is no greenhouse effect by definition.:unquote

        A runaway greenhouse effect is not a clearly defined term, but is understood to mean an event analogous to that which is believed to have happened in the early history of Venus, where positive feedback increased the strength of its greenhouse effect until its oceans boiled away.


        The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.[1][2]
        You appear to be making up your own definitions as you go. The co2 is very active in holding the radiation in the lower atmosphere of Venus. At one time Venus was out of balance at the top of the atmosphere until the water was evaporated away and lost to space. There is not a definition that says there is no green house effect with out the sun. Without the sun Venus would cool. It maintains its temperature dueto  co2 reradiating infrared. CO2 does not care about the source of energy. The sun does not have to be in the defintion of the green house effect.

      7. http://en.wikipedia.org/wiki/Climate_change_feedback
        1 Positive 1.1 Carbon cycle feedbacks
        1.1.1 Arctic methane release Methane release from melting permafrost peat bogs Methane release from hydrates1.1.2 Abrupt increases in atmospheric methane1.1.3 Decomposition1.1.4 Peat decomposition1.1.5 Rainforest drying1.1.6 Forest fires1.1.7 Desertification1.1.8 CO2 in the oceans
        1.2 Cloud feedback
        1.3 Gas release
        1.4 Ice-albedo feedback
        1.5 Water vapor feedback2 Negative 2.1 Carbon cycle 2.1.1 Le Chatelier’s principle
        2.1.2 Chemical weathering
        2.1.3 Net Primary Productivity2.2 Lapse rate2.3 Blackbody radiation
        The last two feedbacks are really the only feedbacks that you can hang your hat on to possibly counteract all the positive feedbacks. The others are slower or will not have enough effect in the long run.
        Thus, although there continues to be some
        uncertainty about its exact magnitude, the
        water vapor feedback is virtually certain to be
        strongly positive, with most evidence supporting
        a magnitude of 1.5 to 2.0 W/m2/K, sufficient
        to roughly double the warming that would otherwise occur.
        Scientists are saying with quite a bit of certainty that water vapor feedback is quite strong.

  4. John,

    The empirical evidence presented in the post clearly shows that humidity, i.e., water vapor causes a cooling effect on surface temperatures.  That is indeed a negative feedback.  Heat is transported away from the surface by convection; what happens after that is not the subject of the post.  But, the heat must eventually find its way back into space perhaps via a mechanism such as the “Iris effect.”

    As for the graph, you are confusing a time-series with the data actually presented: CO2 vs temperature.  The curves are calculated with a form of this formula:  Tc = αln(C2/C1), where Tc is the change in  temperature in degrees Centigrade and the term ln(C2/C1) is the natural logarithm of the CO2 concentration at time two divided by the concentration at time one.   The constant α (alpha) is sometimes called the sensitivity and its value is subject to debate.  This relationship was proposed by Svante August Arrhenius, a physicist and chemist, around 1896. 

    You are also misunderstanding the “more and more” part.  Because the relationship between CO2 and temperature is logarithmic, the “more and more” is more akin to orders of magnitude more, not just linearly “more and more.”  For instance if a doubling of CO2 produces 1 degree of temperature change, the next degree of temperature change requires 4 times the CO2, then 8 times etc.

    The value of alpha, or the sensitivity is the big argument, nobody knows what is really is, but empirical evidence suggests it is low.

    1. All that Brehmer and Sweger showed was a negative correlation between humidity and temperature for a few selected locations. Not a causal negative water vapor feedback for the Global Climate. No evidence was presented that even their correlation could be a proxy for the entire planet. They might as well have said, “it snowed in Utah and Colorado last week so it therefore must have snowed over the entire Globe.” Come on Jon, you can’t seriously believe that the two papers you showed us have now upset 50 years of climate research, including that of true skeptics like Spencer, Christy and Lindzen. 

      Regarding the logarithmic versus exponential graphs. You correctly stated that the logarithmic equation that defines a graph is simply the inverse of the exponential equation that produces the same graph. What I’m looking to NOAA for is an explanation of why they said that CO2 emissions were increasing exponentially. If that is actually mathematically correct, then the inverse of the equation that describes that rate increase, would indeed be logarithmic. No big deal. Let’s see what they have to say. 

      Jon, I fully understand the “more and more” part. And, even if the rate of CO2 emissions turns out to be exponential in the strictest mathematical sense, I’m not arguing that there is an equivalency. But THERE IS an effect. That effect is observable, and within limits, measurable. Most importantly it is included in the calculations of our likely climate future. As Dr. Spencer stated. More and more CO2=more heat. It’s a matter of how much, not if.

      Of course your elementary formula is correct, as is your statement (vast understatement?) that “…sensitivity and it’s value are subject to debate.” That really is the issue isn’t it. And it’s why it’s frustrating to some of us for the debate to turn to:

      1. arguments that the greenhouse effect does not exist at all because it violates the Second Law of Thermodynamics

      2. arguments  about the cause and effect of the observed increase of atmospheric carbon dioxide

      3. arguments about conspiracies to suppress the facts

      4. arguments about the concentration of atmospheric CO2 being so small that they can’t see how it could possibly change global temperature

      Those four are from your Singer article. And this, from your Spencer article:

      “…arguments between us and the anti-greenhouse advocates often become technical and devolve into disputes over the 1st or 2nd Law of Thermodynamics, whether photons really exist, whether a carbon dioxide molecule which absorbs IR energy immediately releases it again, whether outer space is an ‘insulator’, etc.”

      There are real unanswered questions. And they pretty much all revolve around the sensitivity issue. Brehmer and Sweger’s unreviewed opinion pieces, and others like them, do little more than distract from the serious work being done about the fundamental issue of climate sensitivity.

      I really liked where you were going with your closing sentence. Until the last six words: “empirical evidence suggests it is low.”
      Jon, you asked me for the evidence I had for AWG. I presented a concise list of that evidence. You didn’t accept it, and that’s your prerogative. But I now ask that you do the same. Provide a list of your evidence that climate sensitivity is low.   JP

    2. quote: But, the heat must eventually find its way back into space perhaps via a mechanism such as the “Iris effect.”:unquote

      The iris hypothesis is a hypothesis proposed by Professor Richard Lindzen in 2001 that suggested increased sea surface temperature in the tropics would result in reduced cirrus clouds and thus more infrared radiation leakage from Earth’s atmosphere. His study of observed changes in cloud coverage and modeled effects on infrared radiation released to space as a result supported the hypothesis.[1] This suggested infrared radiation leakage was hypothesized to be a negative feedback in which an initial warming would result in an overall cooling of the surface.

       The consensus view is that increased sea surface temperature would result in increased cirrus clouds and reduced infrared radiation leakage and therefore a positive feedback.

      Wong summarized a few basic problems that led to the surprising finding: 
      1. Lindzen and Choi focused on a number of selective time periods. But if the beginning and end points of those time periods are adjusted only slightly, their result falls apart.
      2. The paper also treated the tropics as a closed system. In other words, it did not take into account any outside influences on what was happening in the tropics, such as the large amount of energy transport moving in and out of the tropics on ocean currents and atmospheric waves during events such as El Nino and La Nina.“The tropics is not a closed system,” Wong said. “But they treated it as such in the study.”
      3. Lindzen and Choi took their result from the tropics and applied it globally, instead of using global data to study the link between global temperature increases and global outgoing radiation to space.

      Lindzen came up with 70 watts/M*2 negative feedback whereas Lin from Nasa Langley says Lindzen is incorrect and there is 2 watts/M*2 pos feedback.
      Both Lindzen and Spencer have been shown to do quite poorly in writing good science papers. Spencer’s paper was so agregious that aan editor resigned in embarassment to save the reputation of his journal.

  5. Note for any readers still following this discussion, the graph in question in the comment above is:

  6. Evidence for low sensitivity to carbon dioxide:
    General: in spite of constantly increasing concentration of carbon dioxide in the atmosphere, we still see the normal temperature fluctuations driven by solar cycles and the resulting weather system oscillations.

    More specifically:
    Spencer blog, 2010, The Illusion of a Sensitive Climate System 

    Spencer blog, 2011, Further Evidence of Low Climate Sensitivity from NASAï¾’s Aqua Satellite

    Spencer, 2007, Cirrus Disappearance: Warming Might Thin Heat-Trapping Clouds [link]

    Lindzen & Choi, 2011, On the Observational Determination of Climate Sensitivity and Its Implications, Asia-Pacific J. Atmos. Sci., 47(4), 377-390, 2011.

    Gillett, N.P., et al., 2012. Improved constraints on 21st-century warming derived using 160 years of temperature observations. Geophysical Research Letters, 39, L01704, doi:10.1029/2011GL050226.

    Padilla, L. E., G. K. Vallis, and C. W. Rowley, 2011. Probabilistic estimates of transient climate sensitivity subject to uncertainty in forcing and natural variability. Journal of Climate, 24, 5521-5537, doi:10.1175/2011JCL13989.1.

    Schmittner, A., et al., 2011. Climate sensitivity estimated from temperature reconstructions of the Last Glacial Maximum, Science, 344, 1385-1388, DOI: 10.1126/science.1203513.

    1. Thanks Jon. I’m reviewing your material. I’m pleased that we are going to be discussing the heart of the scientific debate, climate sensitivity. JP

    2. http://www.drroyspencer.com/2010/04/the-illusion-of-a-sensitive-climate-system-a-stovetop-demonstration/

      This is an interesting illustration. But one part of his model doesn’t apply to the earth’s climate. The sun is ever so mildly decreasing its output to the earth and yet we are warming at the same time. We have a reasonably constant source of heat. The stove cannot represent the sun in this case. If the stove represents the co2, we would have to have a different conversation than the one provided by Dr. Spencer.


    3. http://www.drroyspencer.com/2011/01/update-further-evidence-of-low-climate-sensitivity-from-nasas-aqua-satellite/

      quote spencer/
      I found that a 70 meter deep layer provided about the right RATIO between the satellite-observed monthly radiative variations (0.8 Watts per sq. meter standard deviation) and SST variations (0.08 deg. C standard deviation). At the same time, I had to adjust the magnitude of the radiative forcing to get about the right ABSOLUTE MAGNITUDES for those standard deviation statistics, too.
      unquote spencer/

      It appears he tweaked his model to fit the results. That is a very big no no in science.



      Here are criticisms of both Spencer and Lindzen who have quite faulty papers in their basic approach to prove their points.

    4. Spencer, 2007, Cirrus Disappearance: Warming Might Thin Heat-Trapping Clouds

      Lin’s team took the measurements made every day by CERES over the tropical oceans and plugged them into the same model that Lindzen used. Instead of the strong negative feedback that Lindzen’s team found, Lin’s team found a weak positive feedback (Lin et al. 2001). That is, Lin found that clouds in the tropics do change in response to warmer sea surface temperatures, but that the cloud changes serve to slightly enhance warming at the surface. Specifically, whereas Lindzen’s experiment predicts that cirrus clouds change in extent to reduce warming at the surface by anywhere from 0.45 to 1.1 degrees, Lin’s experiment predicts that changes in the tropical clouds will help warm the surface by anywhere from 0.05 to 0.1 degree (Lin et al. 2001).

      This suggests the opposite of Spencer’s article. Not only has Lin found by the data that there is slight pos feedback from clouds but so has Dessler.



    5. http://www.skepticalscience.com/detailed-look-at-climate-sensitivity.html
      Figure 3: Distributions and ranges for climate sensitivity from different lines of evidence. The circle indicates the most likely value. The thin colored bars indicate very likely value (more than 90% probability). The thicker colored bars indicate likely values (more than 66% probability). Dashed lines indicate no robust constraint on an upper bound. The IPCC likely range (2 to 4.5°C) and most likely value (3°C) are indicated by the vertical grey bar and black line, respectively.
      Here is a study showing a variety of methods in a variety of disciplins calculating climate sensitivity. There are low climate sensitivities being calsulated. But then why aren’t you looking at the very high ones? Those are out there also. If you don’t have a wide focus in this, how will you really be able to take in the big picture?

      Source: Skeptical Science (http://s.tt/17Jge

    NOTE: most material in quotes is from JP followed by Adam’s response.

    My reply to JP. Appreciate it if you could post it.

    JP once again, sorry it’s taken a few days to reply.

    “From your opening statement it appears that you have no specific mechanism in mind to account for the warming you agree has been taking place in our climate. ”

    JP please read my comments more carefully. I never said that just a single mechanism could explain 20th century climate change, but a multitude of different natural forces acting on the climate like solar variation, cosmic ray flux, and oceanic oscilations like the AMO.  And once again I suggest that you read Scafettta’s papers which contain detailed discussion of the natural influences on the climate. And you might also like to know that he has just published a new paper.

    “I’ll be happy to get into the weeds regarding GCR theory Adam, if you will first explain one thing to me. If GCR is causing the warming we see, how is it that a solar mechanism causes warming which is more pronounced during the night than during the day?”

    I’m assuming that you got that from John Cook. Nights warming faster than days is perfectly compatible with natural drivers of climate change. Read this link here

    “And if it’s not GCR’s but some other solar mechanism, how does it heat the troposphere while at the same time cool the stratosphere?”

    Once again read my previous comments. There are numerous factors which can explain stratospheric cooling. And might I once again remind you that there has been no cooling in the stratosphere since 1995. It has also been theorised that the different lengths of the solar cycles might affect natural el nino events. This would not lead to warming in the stratopshere and is perfectly consistent with observations. Read this link

    “Additionally, whether cosmic rays are correlated with climate or not, they have been regularly measured by the neutron monitor at Climax Station (Colorado) since 1953 and show no long term trend. No trend = no explanation for current changes.”

    Now that is interesting. I gave you a link showing that that statement was not true.
    In fact I clearly stated “you look at the graph shown in the link
    you will see that for the past three decades, each of the peaks of CR flux was lower than the previous one. If the CR theory was correct, this would have caused warming.”

    JP I understand that I’ve been giving a lot of links, and that it would be very difficult for you to look at all of them, but might I once again ask you to just try and read my comments more carefully.
    Look at this graph here of measurements of cosmic rays, compared to temps (sorry its in German)

    “I suggest that the “solar amplification” you are looking for is CO2.
    When you talk about “amplifiers”, you’re just using a different word for feedback.”

    JP you are wrong. CO2 has nothing to do with the effect of solar activity on climate, and it is certainly not the amplifier. CR’s are the most plausilble amplifier, but it is not the only evidence for it. I recommend that you read this paper here, which provides strong evidence in support of a solar amplification mechanism

    “Last point on this first topic, you once again point me to a list of papers. Adam, you need to be specific about what paper (and what part of that paper) pertains to which argument (and what part of that argument). It’s no good to hand me a pile of journal articles expecting me to pick out the appropriate reference. You need to properly cite your references. I acknowledge that you often do this correctly, so I know you know the difference.”

    Well, I’d say that the best papers for you to look at would be these two here

    “”Comments in blogs and forums do not warrant a reply because any valid criticism would follow the established peer-review process of submitting a comment for publication in the same journal, which allows the author of the original paper a chance to publish a rebuttal in defense of their paper.” Do you recognize that quote Adam? ”

    Yes JP. And I understand that every author has the right to respond to the criticism of their paper. But what I am saying is that you can’t simply dismiss them simply because their “opinion pieces”. Just because they haven’t been peer reviewed that doesn’t mean they’re wrong. And once again I understand the problems of the author not being able to respond, but still you can check the facts for yourself if you want. Nir Shaviv pointed out that over the past 3 decades each of the peaks in cosmic ray flux was lower than the last. This is an empirical measured FACT. And you can check it for yourself. You can’t simply dismiss his piece outright simply because you don’t like that it wasn’t peer reviewed. And Alec Rawls also showed that for the past few decades solar activity was at it’s highest in centuries. This is also a FACT, which you can check for yourself if you want. JP how about actually looking at the evidence, rather than just sorting things into categories of peer reviewed and non-peer reviewed?

    “For now, I’ll just leave you with this quote from the man himself:  “These [Scarfetta’s] results, while confirming that anthropogenic-added climate forcing might have progressively played a dominant role in climate change during the last century, also suggest that the solar impact on climate change during the same period is significantly stronger than what some theoretical models have predicted.”  Does that sound like a refutation of AGW to you?”

    JP that quotes is from one of his older studies, published 6 years ago. More recent data and scientific evidence (as demonstrated in his later papers) have shown that the sun and celestial cycles did cause the majority of 20th cenury warming.

    Quotes from his more recent papers:

    “The non equilibrium thermodynamic models we used suggest that the Sun is influencing climate significantly more than the IPCC report claims. If climate is as sensitive to solar changes as the above phenomenological findings suggest, the current anthropogenic contribution to global warming is significantly overestimated. We estimate that the Sun could account for as much as 69% of the increase in Earth’s average temperature, depending on the TSI reconstruction used.5 Furthermore, if the Sun does cool off, as some solar forecasts predict will happen over the next few decades, that cooling could stabilize Earth’s climate and avoid the catastrophic consequences predicted in the IPCC report.”


    “The IPCC (2007) claim that the solar contribution to climate change since 1950 is negligible may be based on wrong solar data in addition to the fact that the EBMs and GCMs there used are missing or poorly modeling several climate mechanisms that would significantly amplify the solar effect on climate. When taken into account the entire range of possible TSI satellite composite since 1980, the solar contribution to climate change ranges from a slight cooling to a significant warming, which can be as large as 65% of the total observed global warming.”

    “A phenomenological
    model based on the se astronomical cycles can be used to well reconstruct the temperature oscillations
    since 1850 and to make partial forecasts for the 21stcentury. It is found that at least 60%of the global
    warming observed since 1970 has been induced by the combined effect of the above natural climate
    oscillations.The partial forecast indicates that climate may stabilize or cool until2 030–2040.Possible
    physical mechanisms are qualitatively discussed  with an emphasis on the phenomenon of collective”

    “On secular,millenarian and larger timescales astronomical
    oscillations and solar changes drive climate variations. Shaviv’s
    theory (2003) can explain the large 145Myr climate oscillations
    during the last 600million years. Milankovic’s theory(1941) can
    explain themulti-millennial climate oscillations observed during
    the last1000kyr.Climate oscillations with periods of 2500,1500,
    and 1000 years during the last10,000year(theHolocene)are
    correlated to equivalent solar cycles that caused the Minoan,
    Roman, Medieval and Modern warm periods”

    “The existenceofa60-yearnaturalcycleintheclimatesystem,
    whichisclearlyproveninmultiplestudiesandhereinin Figs.2,6,10
    and 12, indicatesthattheAGWTpromotedbythe IPCC(2007),
    is anthropogenic,iserroneous.Infact,since1970aglobalwarming
    of about0.5 1C hasbeenobserved.However,from1970to2000the
    60-year naturalcyclewasinhiswarmingphaseandhascontributed
    no lessthan0.3 1C oftheobserved0.51Cwarming,as Fig. 10B shows.
    Thus, atleast60%oftheobservedwarmingsince1970hasbeen
    naturally induced.”

    forecasting climatechangesduringthenextfewdecades.Over
    this time,theglobalsurfacetemperaturewilllikelyremain
    approximately steady,oractuallycool.”

    And read his later papers



    “Does that sound like a refutation of AGW to you?”

    I know that was a rhetorical question, but still YES his papers clearly show the evidence of natural oscillations being the primary drivers of climate change.

    “Next in your comment, you proceed to show me some “real world data” from an “astrophysicist who has published in the peer-reviewed literature”. Well why not show me the peer-reviewed data?”

    I have showed you peer reviewed data.

    “You go on to say that many studies (which one’s please) “… ignore the fact that in recent decades the sun has been more active than centuries.” I assume you meant “in centuries”.”

    JP papers like Lockwood and Solanski only focus on trend of solar activity. They ignore the ‘pulsing’ of the sun.
    Look at this graph


    You can clearly see the LEVEL of solar activity through the past three decades being the highest in centuries. This could have caused a warming over the period.

    “But an increase in CCN’s (Cloud Condensation Nuclei) most certainly has not. ”

    JP I suggest that you read this paper

    “Look at the work of Pierce and Adams from Carnegie Mellon”

    JP Pierce and Adams used a computer model. They did not use real world data. Svensmark has experimental evidence to back up his theory. Therre is also the very clear correlation between CR’s and clouds, as well as the geological evidence for his theory. Real world data bets models every time.

    “Do I get to assume he’s wrong if temps don’t go down in the next…oh, let’s say six years? No I don’t. Because trends of less than thirty years are weather trends not climate trends.”

    JP once again please read my comments. For the last 10-15 years greenhouse gas forcing on the climate was meant to be at its maximum yet little to no warming occurred. None of the models predicted that. I also think that skeptics Vahrenholt and Luning answer your argument the best

    “Next, Feulner tries to score points by using the 30-year climate rule. In some official definitions, climate is defined as the 30-year mean of weather. While this makes sense for some considerations, this rigid rule obstructs the discussion on the mechanisms that are involved in climate. It’s becoming increasingly clear that natural decadal cycles have been greatly under-estimated in the past. For example the Pacific Decadal Oscillation (PDO) is characterized by a warm and a cold phase, each lasting 20 to 30 years. They have a significant impact on global temperature. Should that 30-year-climate window unfortunately get placed between both phases, then the trends get mixed up and we end up comparing apples and oranges. The corresponding “climate“ results end up depending more on the choice of the start point of the 30-year window and less on the real, shorter-scale temperature trends. Consequently, looking at 10-year temperature trends is not only legitimate, but it also makes sense.”


    “Adam, do you honestly believe that coupled GCM’s do not include changes in ocean heat content?”

    I didn’t mean that they didn’t include changes in OHC. Merely that they don’t have a proper understanding of it. Models present a very simplistic view of the climate system, and are not supported by real world data. Not one of the models predicted the lack of increase in OHC as shown by Douglass and Knox’s paper

    “I assume by “ocean content” you meant “ocean heat content”, or perhaps that’s just another example of MY lack of understanding.”

    It was just a simple typing mistake. There is no need to be snarkey about it.

    “Because you think my understanding is so limited, please translate Mr. Rodger’s sentence for me. ”

    I clearly explained it you in my previous comment. But I don’t see why that one sentence is so important. If you want more information, then I suggest you contact Norman Rogers and ask him.

    “You say that if “stratospheric cooling were due to greenhouse gases, you would have expected the temperature to go down in a clear linear long term  decline.” Why? Did somebody shut off ENSO? ”

    No I was simply stating the prediction of of the climate models. The models can’t fully account for the effects of ENSO. But, again you keep using the ‘short term trends’ and ‘natural variability’ explanation, so here is a question to you:

    What scientific/empirical evidence is there that the decrease in stratospheric temperature (which ended in 1995) was due to human emissions of CO2?

    That’s a simple question. Perhaps you would care to answer it

    “The upper stratosphere is going down even more dramatically. Looks like NASA was right and that would mean you were… wrong.  ”

    JP please provide a graph showing significantly cooling in the stratosphere since 1995?

    And there is also evidence that CFC’s may have played a significant part in stratospheric cooling.

    “And in your very next sentence: “Sorry JP, I’m not the one whose been making any errors.” Oh, the irony.”

    JP once again there is no need to be snarkey. Once again please provide a graph supporting your claims.

    “ut it doesn’t stop. Adam: “It is not the number of papers repeating an argument, but the actual data and evidence.” And again, three paragraphs later: “What I was trying to show was that there are indeed numerous papers showing that the sun is the dominant driver of climate.”  So it’s “not the number of papers”, except if they’re “numerous”? Like a farmer plowing a field Adam, you need to turn around every so often, and see where you’ve just been.”

    JP you are taking my phrases out of context. It is clear that I was not using the simple fact that there were “numerous” papers supporting solar driven climate change as an argument, but the actual EVIDENCE AND DATA which was provided in those studies, especially in Scafetta’s. Please try better to understand my arguments.

    ” Because there has been no quantification of the effects of a mechanism that could be a solar feedback (e.g., GCR), there is no way to include such a mechanism in a model. If (and when) such mechanisms can be confirmed and their effect quantified, they would surely be incorporated. Until then, what are climatologists supposed to do; assume there’s such a mechanism and guess it’s radiative forcing. ”

    Exactly. You’ve just acknowledged that the models are too limited to have proper understanding of the true nature in which natural forces control our climate. JP these simple facts about what the models are missing clearly show that they are not a reliable source for predicting climate events.

    “If you want to exchange your, or other’s, hypotheses; with specific references to observations; I’d be interested to see them.”

    I did give you specific references to papers supporting the major role of oceanic oscillations in climate. If you looked at the links I provided you would see that. And Chris De Freitas’ talk was based on a paper he has published in the peer reviewed literature.

    “Adam, I’ve looked at more than two hundred links you directed me to. I ask you now to see this one video. It’s less than two minutes long.”

    I watched the video. And once again, might I say that short term trends of 2-3 years is cherrypicking, since there is the power of natural variability on the long term trend. But 10-15 years is not cherrypicking. Once again I refer you to the statement by Vahrenholt.

    “Okay, Muller is not what he says he was. He’s what YOU say he was. It must be great to know more about other people than they know about themselves.”

    Once again. PLEASE READ THE LINKS. Muller was quoted numerous times stating that he believed humans were causing GW. DO you deny thst he said this?

    “The BEST studies account for UHI. It’s not even that difficult. Read how they do it. What study or studies of GST’s do you think are accurate? I’m guessing none, because they ALL AGREE.”

    Once again you have STILL not answered all of the points that was raised regarding the BEST data in the links I gave you.

    “”Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences. “The report identified and corrected errors in satellite temperature measurements and other temperature observations, which increased scientific confidence in the conclusion that the lower atmosphere is warming on a global scale: “There is no longer a discrepancy in the rate of global average temperature increase for the surface compared with higher levels in the atmosphere”.”

    There conclusion is not supported by real world data. Once again please look at the graph I provided of GISS temps to UAH temps.

    “For example, skeptic Roy Spencer provides a graph of the UAH/MSU data which he updates monthly. He always shows the running 13 month mean AND the third polynomial fit. Others add least squares. Each gives a little different view of the trend. The same fit over different time frames is simply a way to view rate changes. ”

    Roy spencer was plotting the long term average over that period. He was not simply cherry picking his start dates and applying multiple trend lines as was done in the IPCC’s report. What he did was completely different.

    “Do you know what the temperature difference above and below a  Halocline can be? Easily 2 degrees C, and sometimes more.”

    Yes, but that’s irrelevant. There is still no way the IR supposedly reaching the Earth by CO2 could pass through the first 700m undetected and just magically show up below it. You’d still show the first 700m to show a very clear heating pattern. You have still not answered this.

    “As for your assertion that the top 700 meters would necessarily contain more of the excess heat from AGW, considering that NOAA states that the average depth of the worlds oceans is 4,267 meters, you might want to reconsider that calculation.”

    Once again, how is the total depth relevant? The IR would have to pass through the first 700m, in order to warm the area below it. Fact.

    “Remember, it’s the CHANGE in heat content within both bodies that is determinative.”

    Yes, but the change is not what is predicted. Once again I refer you to Douglass and Knox paper.

    “Could you explain this sentence please: “I think that you’ve scored an own goal with that comment there.” Does that mean I won?”

    No that does not mean that you have won. Do you know what an own goal is?

    Anyway JP, I’m going to be going away for a week, so I’m not going to be able to continue this debate. If you want to continue next week, or just agree to disagree, then that’s your choice.

    1. Gee Adam. We have to answer all your questions or you win. Is that correct? On the skeptic (denier) side of the equation, there are woefully inadequate explanations for why the earth is warming. There is no winning on the skeptic side unless a better explanation is provided than the IPCC has shown us.

    2. Hi Adam. Sure, we can continue when you return. Let me know when you get back. Have a safe journey. JP

    3. Adam, For solar activity & climate see this:


      And this on solar variability:


      And this on solar irradiance:


      This will show solar effect after removing others:


      See this for solar cycle variability:


      And here you’ll see how the solar magnetic field has not changed  appreciably for three decades:


      For evolution of solar magnetic flux over decades to millennia:


      You should read this on the effects of GCR’s on cloud nucleation:


      And here on GCR’s and cloud cover:


      This will explain GCR’s and the four major cloud formation parameters:


      Adam, are you seeing what it’s like to address one of your posts or would you like me to go on? And on. And on……..   JP

  8. Posted for Adam:

    JP I’m back. I’ve had to sort some stuff out for the past few days, which is why I haven’t had time to respond straight away 
    1. I couldn’t find a PDF for this paper here 
    so I can’t really comment on the arguments presented. But in their abstract nowhere do they consider possible amplification mechanisms of solar activity like Svensmarks cosmic ray theory or Scafetta’s astronomical oscillations 
    This paper here seems to confirm the solar-climate relationship, so I’m not sure why you linked to it 
    This paper here doesn’t really mention any solar affect on climate, it simply focuses on the changes in TSI over the past few centuries 
    As for this paper 
    I recommend you read these critiques 
    “And here you’ll see how the solar magnetic field has not changed appreciably for three decades: 

    JP I have responded to this argument many times in my comments. Please read the links I provided. 
    This paper here also doesn’t really mention any solar effect on climate, it just focuses on reconstructing TSI changes 

    You should read this on the effects of GCR’s on cloud nucleation: 
    And here on GCR’s and cloud cover: 
    This will explain GCR’s and the four major cloud formation parameters: 
    First of Kazil’s paper is out of date. It was written before it was shown by the SKY experiment that cosmic rays do indeed affect the production of aerosols in the atmopshere. Other recent papers by Svensmark have also confirmed this.
    I am aware of the papers by Sloan and Wolfendale and Kristjanson. I recommend that you read these critiques of those papers 
    And I know that you’re probably going to claim that they’re not peer reviewed so they don’t count, but just so you know Svensmark has indeed responded to those papers in the peer reviewed literature 

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